Process of making indolic bodies.



UNITED STATES PATENT OFFICE.

PAUL SEIDEL, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSIGNOR TO THEBADISOHE ANILIN UND SODAFABRIK, OF LUDVVIGSHAFEN- ON-THE-RHINE, GERMANY,A CORPORATION OF BADEN.

PROCESS OF MAKING INDOLIC BODIES.

Specification of Letters Patent.

Patented. Aug. 29, 1905.

Application filed October 24, 1902- Serial No.128,616.

To It when it "La/ll] concern:

Be it known that I, PAUL SEIDEL, doctor of philosophy and chemist, asubject of the King of Saxony, residing at Ludwigshafen-on-the- Rhine,in the Kingdom of Bavaria, Empire of Germany, have invented new anduseful Improvements in the Process of Manufacturing Indolic Bodies, ofwhich the following is a specification.

I have discovered that indol is or indolic bodies are contained in andcan be isolated from melts such as are'olotained by heating bodiescontaining the chemical group R-N- OHZ'OO (in which R signifies anaromatic radicall-for instance, bodies such as phenylglycin,tolyl-glycin, phenyl-glycin-ortho-carboxylic acid, a salt, ester, amid,anilid, or anhydrid of one of these bodies, and the like, and whichbodies I will refer to generically as phenyl-glycin substances Withalkaline dehydrating agents, such as hydroxids or oxids of the alkaliesor alkali earths, either alone or in admixture with inorganic bodieswhich decompose Water.

By my invention I effect an improvement in the manufacture of indigo,for from the Waste liquors I recover a valuable by-product, thuscheapening the manufacture of indigo itself. Further, I can by varyingthe conditions of the melting operation increase the quantity of theby-product, for the quantity of indol formed apparently increases(within certain limits) with the temperature. The addition to the meltof reducing agentssuch as finely-divided iron powder, sulfite salts,sodium ethylate, and the likealso augments the yield of indol.

The following examples will serve to further illustrate the nature of myinvention; but the invention is not confined to these examples and theconditions described therein. The parts are by weight.

Example 1: Intimately grind together two hundred (200) parts ofphenyl-glycin-orthocarboxylic acid potassium salt and five hundred (500)parts of caustic potash. Heat the mixture for two (2) hours at atemperature of two hundred and ninety degrees centigrade, (290 C.) Whencool, dissolve the melt in two hundred (200) times its weight of water,and oxidize this solution by means of air or other suitable agent untilno more indigo is precipitated, and filter and isolate the indol fromthe filtrate, either by extraction by means of ether, benzene, or othersuitable solvent, or by distilling it in steam. The indol which distilsover with the steam can be isolated from the aqueous distillate in anysuitable manner-for example, by treating it with a one (1) per cent.solution of picric acid and as much sulfuric acid (containing aboutfifty (50) per cent. HgSOl) as is equal to ten (10) times the quantityof picric acid employed. The precipitate of indol picrate obtained isthen worked up forindol, which can be done in the known manner. Ifdesired, the indol can be isolated from the solutions of the melt beforeseparating indigo therefrom.

Example 2: Intimately mix together two hundred (200) parts ofphenyl-glycin-orthocarboxylic acid sodium salt, four hundred (400) partsof caustic soda, and fifty (50) parts of iron powder. Heat the whole forabout two (2) hours at a temperature of from two hundred and eighty tothree hundred degrees Centigrade, (280 -300 O.) \Vork up the melt asexplained in the preceding example.

Example 3: Intimately mix together two hundred (200) parts ofphenyl-glycin potassium salt or two hundred (200) parts ofphenyl-glycin-ethyl-ester,two hundred (200) parts of caustic potash, twohundred (200) parts of caustic soda,four hundred (400) parts of causticlime, and one hundred (100) parts of anhydrous sodium sulfite. Heat themixture for about two (2) hours at a temperature of three hundreddegrees centigrade (300 O.) and work up the melt as explained in thepreceding Example 1.

I claim 1. The process of making and isolating indolic bodies by-heatinga phenyl-glycin substance with an alkaline dehydrating agent, dissolvingthe melt, treating with an oxidizing agent, getting rid of the indigoprecipitated, and from the liquor so obtained isolating the indolformed. I

2. The process of making and isolating indolic bodies by heating aphenyl-glycin substance with caustic alkaline substance, dissolving themelt, treating with an oxidizing agent, getting rid of the indigoprecipitated, and from the liquor so obtained isolating the indolformed.

3. The process of making and isolating indolic bodies by heating aphenyl-glycin Slll).

stance With an alkaline dehydrating agent and a reducing agent,dissolving the melt, treating With an oxidizing agent, getting rid ofthe indigo precipitated and isolating the indol formed,

4. -The process of making and isolating indolic bodies by heating aphenyl-glycin substance With caustic alkaline substance and a reducingagent, dissolving the melt, treating With an oxidizing agent, gettingrid of the indigo precipitated and isolating the indol formed.

5. The process of making and isolating indolic bodies by heating aphenyl-glycin substance with amixture of caustic potash, caustic sodaand caustic lime, dissolving the melt, treating with an oxidizing agent,getting rid of the indigo precipitated and isolating the indol formed.

6. The process of making and isolating indolic bodies by heating aphenyl-glycin substance With a mixture of caustic potash, caustic soda,caustic lime and sodium sulfite dissolving the melt, treating With anoxidizing agent, getting rid of the indigo precipitated and isolatingthe indol formed.

7. The process of making and isolating indolic bodies by heating aphenyl-glycin substance With an alkaline dehydrating agent, dissolvingthe melt, treating With an oxidizing agent, getting rid of the indigoprecipitated,

and from the liquor so obtained isolating the indolic body formed.

8. The process of making and isolating indolic bodies by heating aphenyl-glycin substance With caustic alkaline substance, dissolving themelt, treating With an oxidizing agent, getting rid of the indigoprecipitated, and from the liquor so obtained isolating the indolic bodyformed.

-9. The process of making and isolating indolic bodies by heating aphenyl-glycin substance With an alkaline dehydrating agent and areducing agent, dissolving the melt, treating With an oxidizing agent,getting rid of the indigo precipitated and isolating the indolic bodyformed.

10. The process of making and isolating indolic bodies by heating aphenyl-glycin substance with caustic alkaline substance and a reducingagent, dissolving the melt, treating With an oxidizing agent, gettingrid of the indigo precipitated and isolating the indolic body formed.

In testimony whereof I have hereunto set my hand in the presence of tWosubscribing Witnesses.

PAUL SEIDEL.

Witnesses:

ERNEST F. EHRHARDT, JACOB ADRIAN.

